Tame the Umklapp Processes in Real-Time Lattice Simulation for Hydrodynamics: An Ising Field Theory Study
The study used lattice simulations to calculate real-time correlations of stress-energy tensors for a nonintegrable Ising field theory. It found that Umklapp processes are suppressed in the scaling region, and emergent sound modes characteristic of relativistic hydrodynamics appear at late times and long wavelengths. This demonstrates how lattice methods can reveal hydrodynamic behavior from first principles.